Resin compositions plasticized with dialkyl esters of a mixture of diacids



June 17,1958 6. w. JOHNSTON ETAL 2,839,485

RESIN COMPOSITIONS PLASTICIZED WITH DIAL-KYL- ESTERS OF A MIXTURE OF DIACIDS Filed June 15, 1954 2 Sheets-Sheet 1 0 W F RN 0 NY LE W 5 VIA) D E w EwA mL D L N 5 Y m m TD s U M .M E E Pm DMS E MR 4/ f/ brew; IE-0E0 m0 .Pzmommm w PIG-m3 z wmOJ FIG-I June 17, 1958 c. w. JOHNSTON ETAL 2,839,485 RESIN COMPOSITIONS PLASTICIZED WITH DIALKYL I ESTERS OF A I MIXTURE OF DIACIDS Filed June 15, 1954 I 2 Sheets-Sheet 2 IR 0F MIXED ACIDS D OOTYL SEBAGATE (DOS) IISOOCTYL ESTI ISOSEBACIC RESIN (VINYLITE VYNW) PARTS OF PLASTICIZIIR PER IOO PARTS OF FIG w; Adz-0E0 m0 .FZUOKM CHRISTIAN W. JOHNSTON 7 ROBERT A. MEARA Fl INVENTOR.

United States Patent 2,839,485 Patented June 17, 1958 fiice RESIN COMPOSITIONS PLASTICIZED WITH DI- ALKYL ESTERS OF A MIXTURE F DIACIDS Christian W. Johnston, Severna Park, and Robert A. Meara, Baltimore, Md., assignors to National Distillers and Chemical Corporation, a corporation of Virginia Application June 15, 1954, Serial No. 436,962 8 Claims. (Cl. 260-31.8)

This invention relates broadly to a new class of ester plasticizers from selected mixtures of C diacids and especially relates to mixtures of C diacids which have been discovered to be particularly effective as plasticizers for resinous and rubbery vinyl polymers and copolymers. More specifically, this invention relates to vinyl resin compositions plasticized with selected alkyl esters of C diacid mixtures and especialy the dibutyl, di-Z-octyl, the di-n-octyl, the di-2-ethyl hexyl, and the di-isooctyl esters.

The increasing manufacture and uses of plastic materials such as vinyl resins, polyacrylate resins, polymethylmethacrylate resins, rubbers such as the emulsion copolymers of butadiene with a minor amount of styrene or acrylonitrile, or the copolymers of isobutylene with small amounts of a diolefin such as isoprene or butadiene have created a large demand for suitable plasticizers. This is particularly true in the case of vinyl resins such as vinyl chloride, and copolymers of this material with, for example, vinyl acetate.

The plastics industry requires plasticizers which are non-volatile and which give plastic products showing low extraction by oil, less migration, lower embrittlement temperatures, as well as other improved properties, particularly as regards the many effects of heat and aging.

Numerous alkyl esters and diesters have been proposed and used as plasticizers for resins, especially for the vinyl polymers and copolymers.

Dioctyl sebacate is well known as a plasticizer for its low temperature performance as well as its resistance to extraction by water and soap or detergent solutions. Dioctyl phthalate is a very widely used vinyl resin plasticizer. Dibutyl sebacate and di-Z-ethyl hexyl adipate are both used as specialty plasticizers to give good cold temperature properties but both are quite volatile. These materials also exhibit poor oil extraction properties.

It is an object of this invention to provide a new type of selected alkyl esters. It is a further object of the invention to provide novel diesters having improved plasticizing characteristics especially for vinyl polymers and copolymers. Another object is the production of plastic vinyl resin compositions having good oil extraction properties as well as advantageous low temperature characteristics, high efficiency, good migration characteristics, as well as good properties otherwise. Other objects will be apparent from the subsequent description.

It has now been discovered that new, selected alkyl esters can be derived from esterification and transesterification reactions with isomeric, branched chain C aliphatic diacids and especially a mixture of C diacids made up from and including substantial amounts of Otethylsuberic and u,u-diethyladipic acids. These diacids are preferably obtained as a mixture and by a particular method as further described below. The mixture used for preparing the improved plasticizers is amixture of isomeric aliphatic C diacids and it is important "and 2 necessary that the mixture contain substantial amounts of at least one branched chain isomer.

' It has recently been found that an aliphatic conjugated diolefin can be treated with finely dispersed sodium or potassium in a selected ether medium and in the presence of a relatively small amount of polycyclic aromatic hydrocarbon and/ or a solid attrition agent at a temperature preferably below 0 C. to give a mixture of dimetallo derivatives of the dimerized diolefin. These dimetallo derivatives can then be carbonated at a temperature below 0 to give the corresponding salts of unsaturated dicarboxylic acids in high yields and selectivities.

In the case of initial reaction using sodium and butadiene, the product obtained comprises the disodium derivatives of the aliphatic isomeric octadienes. Studies of the structures of the saturated diacids arising therefrom after carbonation and hydrogenation indicate that mixtures of isomeric C dicarboxylic acids are obtained. Thus, the following final hydrogenation and acidification, the product mixture yields, as the major products, sebacic acid, ot-ethylsuberic acid, and a,a'-diethyladipic acid.

In the preferred type of operation, the butadiene and finely dispersed sodium are reacted in an attrition apparatus such as a ball mill or pebble mill, with a selected solid attrition agent. This material is most conveniently solid sodium chloride. The disodiooctadienes formed are subsequently carbonated to the unsaturated C diacids. Organic solvents are then removed and the solids are converted to an aqueous solution, which is preferably filtered prior to hydrogenation. A catalytic hydrogenation is then carried out to convert all acidic compounds to completely saturated acids.

The resulting final reaction mixture contains varying amounts of sodium salts of isomeric C dicarboxylic acids of which the linear sebacic acid predominates. It also contains the valuable branched chain C acids as well as small amounts of monobasic acids of varying molecular weights from C to C The major portions of the linear isomer sebacic acid can be separated from this mixture, for instance, by saturation of the solution with sodium chloride and addition of controlled amounts of a strong acid. Benzene extraction can also be used. This produces an isomeric mixture of C aliphatic dicarboxylic acids containing from 60-88% wethylsuberic acid, l2-25% of a,a.'-diethyladipic acid, and the remainder, 0-l5%, substantially sebacic acid.

The esters from this mixture are particularly outstanding as plasticizers. The alkyl groups of the diesters can contain 4- or more and, preferably, from 4 to 8, inclusive, carbon atoms, depending on the alcohol used in the esterification.

Particularly outstanding esters can be obtained by preparing diesters from butanol, and an octyl alcohol such as n-octyl, 2-octyl, Z-ethylhexyl, and especially from isooctyl alcohol. The latter expression is used herein to designate a mixture of C alcohols made from a suitable seven-carbon atom olefin mixture by the 0x0 reaction, followed by hydrogenation. These C alcohols are branched chain isomers of octyl alcohol and are of the primary class, for example, see U. S. Patent No. 2,626,284.

The esters useful for the purpose of the present inven-.

tion can be prepared by conventional esterification methods, with or without a catalyst. The preferred method of ester synthesis involves refluxing about 1 mole of the mixed isomeric diacids and about 2 to 2.5 moles of selected alcohol. A diluent such as an inert solvent may be used when convenient for lowering the reflux temperature. The resulting ester is then washed in the usual manner to remove any residual acid and subjected to distillation at reduced pressure (about 1 mm.) to remove excess alcohol and moisture, if any. Alternatively, the desired ester may be made by ester interchange from the dimethyl or diethyl esters.

The results obtained from the compositions of diesters with the vinyl resins show numerous advantages. As compared to known low temperature plasticizers, for instance, dioctyl sebacate, the oil extraction properties are good as are the migration properties. In addition, the plasticizer efficiency and low temperature properties of the compositions are also good. It is this combination of properties which is both surprising and outstanding.

It is entirely unexpected to find that the mixed branched chain esters are better in many properties and give better plasticized compositions than comparable linear products. This is particularly true for the oil extraction properties.

The invention particularly relates to plasticized resin compositions containing the novel diesters as plasticizers, usually in proportions ranging from about 5 to 100 parts or preferably about 30 to 60 parts per 100 parts of resin. Polymeric materials which lend themselves to successful plasticization with the esters of the invention include the various vinyl resins such as polyvinyl chloride, and mixed polymers of vinyl chloride with vinyl acetate. -The diesters show limited compatibility with polyvinyl butyral or other polyvinyl acetals. The diesters can also be used at lower levels of concentration with rubber-like polymers of diolefinic materials such as butadiene-nitrile, butadienestyrene or polychloroprene elastomers, or isobutylenediolefin copolymers or any other polymeric materials customarily requiring plasticization. Mixtures of these from which most of the sebacic acid has been removed shows the following properties:

Boiling point at 2 mm 185205 C. Melting point -55 C. lodine number Less than 1 Neutralization equivalent 101-102 Such a sample has been analyzed to a distribution approximately as follows:

, Percent ot-Ethylsuberic acid a,a.-Diethyladipic acid 10 Sebacic acid 12 In the preparation of the esters, two general procedures were followed: (1) direct esterification of acids with alcohols, with and without catalyst, while removing the water of esterification azeotropically, and (2) transesterification of esters of low boiling alcohols with higher boiling alcohols, using transesterification catalysts, while removing the lower boiling alcohol by rectification.

Reactants were charged to a 2-liter, three-necked flask, provided with stirring (mechanical or magnetic), openings for sampling of the reaction mixture and addition of alcohol, and a nitrogen bleed to exclude oxygen. Low boilers were taken off through a 12-bulb Snyder column (about 6 theoretical plates) which was provided with a fraction cutter or decanter (when azeotropic removal of water was desired). At completion of the reaction the crude diester product was washed or neutralized, then stripped under vacuum with steam or nitrogen. Lower boiling esters were distilled at about 1 mm. vacuum.

Details of the preparation and properties of'the specific diesters prepared are shown in Table I below:

Table I.Ester plasticizer preparations Ester Method of prep- Method of Sap. Sap. Sp. gr.

No. Alcohol reactant Acid reactant aratlon work-up Catalyst value, value, at

found theory 25 C.

1 Z-ethyl hexanoh. Mixed saturated Om di- 'Esteriflcatlon..- Washed, stripped. 0 264 268 .910

acids, most of sebacic 2 Iso-oetanol H 256 263 .912 3 n-Butanol HSO 352 357 .939

classes of materials may also be used. It should be under- EXAMPLE 2 stood that in addition to the plasticizer, the polymer compositions may also contain about 1 to 10 or 25 parts of conventional stabilizers such as basic lead carbonate, lead stearate, cadmium stearate, epoxy fatty acid compounds, or the like, as well as suitable amounts of oleic acid, auxiliary plasticizers or softeners, fillers, pigments and the like.

The following examples will serve to illustrate the present invention, though it will be understood that the invention is not limited thereto, and that certain modifications or variations thereof are possible without departing from the spirit of the invention or from the scope of the appended claims. It will be understood that all quantitative proportions referred to are expressed on a weight basis, unless expressly indicated otherwise.

EXAMPLE 1 The simple diesters of the C dibasic acids were prepared and tested. The C dibasic acids were obtained as mixtures by the selective dimerization of butadiene using finely dispersed sodium in the presence of an ether reaction medium and a small amount of a polycyclic aromatic hydrocarbon and/or a solid attrition agent to obtain a mixture of disodiooctadienes which is then carbonated to yield the mixture of C diacids.

A typical sample of the mixed C aliphatic diacids These new plasticizers and compositions therefrom were compared with dibutyl sebacate, dioctyl sebacate, di-2-ethylhexyl phthalate, and di-Z-ethylhexyl adipate when compounded into a well-known vinyl copolymer, Vinylite VYNW, a copolymer of vinyl chloride and 5% vinyl acetate.

The efiectiveness and various specific properties of the novel diesters as plasticizers and in comparison with well-known diesters were determined by the following method. The liquid ester plasticizer was blended into the vinyl resin powder to give a uniform mixture. This mixture was then worked on the heated mill rolls, for a period of time until it formed a homogeneous plastic mass. The mixture was removed from the mill as a sheet and molded under suitable heat and pressure to form uniform plastic sheet stock. From these sheets, the test specimens are cut.

PROCESSING CHARACTERI STICS The ease of processing of the ester-resin mixture is quite essential. All the new diesters were found to blend into the resins quite satisfactorily. The materials also possessed good properties of lubricity which allows easy separation of the blends from the mill rolls and the mold plates.

TENSILE PROPERTIES;

This test is a convenient means for determining an indication of the approximate hardness of a plastic. It is based on ASTM test D-676-47T.

6 volves holding a strip of plastic under definite tension and bending it repeatedly until failure occurs.

The low temperature performance of the plasticized vinyl resin stock at low temperature when subjected to a hard blow or to flexing is of primary importance. The test used to measure flexibility is carried out by folding the specimen continuouslyunder tension at 0 C.

it has been found that the selected diesters of the mixture of C diacids containing two or more of the isomeric diacids impart outstanding flex and elasticity Particularly are these properties of the new diesters superior to those of the commonly'employed dioctyl phthalate plasticizer. Table II below shows the results from the fold flex tests.

Table II.Co mparative properties of 1 plasticizers Shore A Plasticlzer 100% 1 durometer cone. Tensile elastic Percent hardness Compound strength modulus ultimate at 0. Fold flex,

at 25 0., at 25 0., elong, 0 C.

p. s. l. p. s. i. at 25 0. Percent P/100 Initial After 10 sec.

33. a 50 3, 3001250 1, 520170 270125 90 3, 70011, 500 g g g gi gi g f-l gf $23 313? 23.5 40 3, 7101210 2,1001150 23518 30 39 3101200 S 23.1 30 3, 9001340 2, 9901100 205140 100 98 190115 33. 3 50 3, 180170 1, 740150 260110 75 500140 Di-2-ethy1hexyl phthalate 28. 5 3, 8201210 2, 5501250 230120 95 34 180130 23. 1 30 4. 5001250 4, 0501240 145110 100 97 100150 At 300% elong.

1 3 a es 1 13 11 2 5 B8 1 1 5 2901 0 82 7,90012, 100 sebum 1 2s. 5 40 3, 3001270 2, 0001120 275125 95 39 340170 At 300% elong.

, 33s 50 2 7151105 1 180145 300 77 03 17 150113 000 Dlbutyl esters of mixed saturated C10 di- 28 5 40 4003:130 1 3 1100 283115 85 77 2, 17511, 250 was, sebum acldfemwed- 23.1 30 4, 3751110 2, 7551150 215110 0s 30 230150 at 300% elong.

, l 1 33.3 2, 2301210 970170 300 74 06 100, 000 Dibutyl sebacate 2s. 5 40 3, 2501120 1, 420180 230110 35 2, 7401975 23. 1 30 3, 9501350 2, 170130 220125 94 35 370140 33. 3 50 2, 7101130 1,3301 55 290115 30 72 14, 80017, 000 D1-2-ethylhexyl adipate 28. 5 40 3, 4501140 1, 9001. 55 255130 00 3, 01011, 540 e 1 1 3 rates 3 are a r 5 11 5 1 s5 5 000 2 000 2-0ctyl esters ofmlxed saturated-O10 dlllClClS, 28 5 40 3390i140 0601100 2605:) 93 0,16

r 1150 56mm" acid, emovei 20.0 25 4, 1101200 3, 3101140 250125 00 120130 Sheets of the milled stock are plied up to approximate- PERMANENCE ly 0.25 inch. Using a Shore A 2 duronieter, readings are taken immediately and again after 10 seconds. The values reported in Table II are the averages of 5 read- 111 3.

a nnrtrrnnnnss 'rnsr This test is intended to determine the ability of plastic materials to resist the effect of low temperature in causing them to become brittle so as to cause fracture when they are bent.

Strips of milled stock (resin and plasticizer) are immersed in the tank of the test machine which contains a cooling liquid, and are clamped-at one end of the test strip. The temperature of the cooling liquid is varied in 5 C. intervals. At each temperature interval, the test specimens are subjected to a single sharp blow The brittle temperature is defined as the lowest temperature of non-failure of 5 consecutive test specimens under the specified test conditions. The data are shown in Table III.

FOLD ENDURANCE TEST This is based on ASTM test D-643-43. The test in- 75 It is also a requirement that an article of manufacture should possess its original properties throughout its entire period of use. The plasticizer should not volatilize, it should not be readily extracted by water or soap and detergent solutions, or oils or gasolines and the like, and it should not migrate into adjacent finishes and coatings to soften or mar them. The diester plasticizers show outstanding resistance to migration when incorporated into vinyl compositions when compared with known low-temperature type ester plasticizers. It is a great advantage in that vinyl compositions plasticized with these compounds wi-ll not adhere or stick to lacquer, varnish and paint surfaces.

RESISTANCE TO EXTRACTION E Y WATER, SOAP AND DETERGENT S OLUTION S gent solutions.

analytically and immersed in the water, soap and deter-,

The Water is changed every working day and kept at 25 C, After a week the samples are held for; one hour at 80 C., cooled ina desiccator and weighed. The loss is then calculated.

The soap solution is 1% Ivory Flakes while the detergent solution is 1% Rinso. The samples are put into the solutions at 80 C. and this temperature is maintained for 4-8 hours. The samples are rinsed and then oven dried'at 80 C. for one hour. After coolingin a desiccator, the samples are'weighed and the calculations made.

RESISTANCE 11:0 OIL EXTRACTION This test is a modified procedure of ASTM D -543-43 and is intended for use in determining the resistance of a plastic to a light mineral oil. Test specimens are cut from milled stock and immersed in a clear white mineral oil for 7 days at 25 C. Changesin weight and appearance of the test specimens are observed and reported. The accompanying figure shows a graph in which the comparativezresults of the tests obtained with dioctyl sebacate, dioctyl esters of the mixed acids, dibutyl sebaoate, and dibutyl esters of the mixed acids. Both the dioctyl and dibutyl esters of the mixed saturated C diacids show superior resistance to oil extraction as compared with other well-known low temperature plasticizers; The dibutyl ester is especially outstanding.

MIGRATION This test is a procedure for evaluating the resistance of various surface finishes to plasticized vinyl stocks.

Four test finishes (white enamel, varnish, metal lacquer, and furniture lacquer) are applied to tin panels and allowed to dry for at least one week. Strips of the milled stock are placed in intimate contact with the (slightly larger in diameter than the specimens). A sample is placed on the acid and covered with cc. of acid. The second sample is introduced and covered with 25 cc. of acid. An aluminum foil barrier isinserted andthe arrangement repeated until the can is full. Hardwood fillerblocks (same diameter as samples) are inserted and a "20-pound weight placed on top. The arrangement is left for' four days when the samples are removed, brushed clean and weighed. The percent plasticizer ioss is reported as is the original concentration of plasticizer. The migration test results are shown in TableIl'I}: y M

The comparisons of the well-known and most commonly used vinyl resin plasticizers with the novel diesters n the mixed isomeric C diacid, as shown in Table indicate that the lieu/ plasticizers are in every instance essentially equivalent to the known materials. in some instances, such as in migration, and plasticizer eificiency, these new plasticizers show improved behavior in these tests over the commonly used materials.

EFFICIENCY Using the Scott tensile tester, Model IP-4, the 100% elastic module are obtained from the stock containing various amounts of the plasticizer per 100 parts of the resin by weight.

A graph can then be made by plotting weight of plasticizer vs. the pound. per square inch for 100% elongation. From this graph there is selected the weight of plasticizer which corresponds to 3600 p. s. i.

The efficiency equals the weight of plasticizer per 100 grams of resin to give 100% elongation under a selected degree of loading. The data shown were based upon 3600 pounds per square inch loading.

Table-lII.--C0mparative properties of plasticizers Plasticizer eonc. Oil re- Per- Brittle sist- Percent Percent Percent Compound point, ance, cent s01. water etfi- Per- P/100 G. Perweight matter absorbed cioncy, cent cent incr. lost 3,600 psi.

Di-2-ethylhcxy1 esters of mixed saturated G10 di-aeids, I2 19 0 most of sebacic acid removed. 2&1 3o 6 10 '00 10 33. 3 50 58 .09 .00 .00 Di-2-ethylhexyl phthalate 28. 5 20 29 .07 00 .07 23. 3

23.1 30 10 07 07 .00 .07 39.8 66 61 -16.8 .14 .00 .14 1 Warsaw at it :gt 1 at ;g% it at 23.1 30 -2. 2 .12 .00 .12 i Dibutylcstcrs of mixed saturated Cm diacids, most of 28 sebncie acid removed. 3O 0 12 i 1 33. a -e0 -11.1 .16 I01 I17 Dibutyl sebacate 28. 5 40 6. 7 .19 .03 .22 16. 8

I 23. 1 30 45, 3. 0 14 07 21 v 33. 3 50 -55 5. 5 .11 .04 .15 Di-2-ethylhexyl adipate 28. 5 40 45 -2. 9 11 04 15 22. 2

r -35 .03 .12 2-octyi esters of mixed saturated G10 diacids, most of so.- i T55 5 bacie acid removed. 33- 3 3g 33 3 -33 g3 6 VOLATILITY finishes and stored at 25 C. under 0.25 pound per square inch pressure. At intervals, the specimens and finishes are examined.

The known sebacate plasticizers have the disadvantage of showing marked migration, while the plasticizers from the mixed saturated C diacids limit migration.

Migration can also be measured quantitatively using silicic acid as an absorbent. The test employed was a modification of the method of Grafton and Greenly.

Duplicate specimens, 2.69 inches in diameter and .065 inch thick, are weighed analytically. 25 cc. ofsilicic acid, AR-100 mesh, are placed in a half-pint paint can The method used' to measure the volatility of the plasticizers from thestock was a severe exposure of the stocks in a circulating air oven at 100 C.

The results oftests on a copolymer of vinyl exposure for 7 days at C. in a circulating air-oven.-

The novel esters were, in every case, equivalent to the diesters in use, and in some cases, the new compounds exhibited somewhat better volatility characteristics.

Table lV.-Volatility and stability tests Tensile strength 100% modulus Ultimate Weight loss (1). s. i.) (p. s. i.) elongation (percent) (percent) Compound Of As Before After Before After Before After total p1astleizcr Di-2-ethylhexyl ester of mixed saturated C diaeids, most of sebaeie acid removed 3, 360 3,350 1, 620 2, 300 270 275 10. 7 32.1 Dioctyl sebacate (DO 2, 900 2, 800 l, 590 1, 800 290 255 2. 4 7. 2 Di-Z-ethylhcxyl phthal 3, 320 3, 250 1, 870 2, 260 260 200 5. 9 17. 7 Dibutyl sebacate (DBS) 28.9 86.7 Dibutyl ester of mixed saturated Cm diacids, most of sebaeic acid removed 2, 715 4, 150 l, 180 300 100 21. 8 65.5 Di-2-ethy1hexyl adipate (D 0A) 2, 710 3, 200 1, 330 2,200 290 210 11.3 33.7

1 Too brittle to test. 1 At 300% elongation.

What is claimed is: 5. A composition of matter of claim 2 in which the 1. A composition of matter comprising 100 parts by weight of a vinyl resin selected from the group consisting of polymethylmethacrylate resin, vinyl chloride resins, and polyvinyl acetals, and from 5 parts to 100 parts by weight of a plasticizer consisting essentially of dialkyl esters, in which the alkyl group has from 4 to 8, inclusive, carbon atoms, of a mixture of C aliphatic isomeric diacids consisting essentially of about 60-88% u-ethylsuberic acid, and the remainder of the diacids consisting of a mixture of u,ot'-diethyladipic acid and sebacic acid.

2. A composition of matter comprising 100 parts by weight of a vinyl resin selected from the group consisting of polymethylmethacrylate resins, vinyl chloride resins, and polyvinyl acetals, and from 5 parts to 100 parts by weight of a plasticizer consisting essentially of dialkyl esters, in which the alkyl group has from 4 to 8, inclusive, carbon atoms, of a mixture of C aliphatic isomeric diacids consisting essentially of about 6088% u-ethylsuberic acid, about 1025% of a,a'-diethyladipic acid, and the remainder, sebacic acid.

3. A composition of matter of claim 2 in which the dialkyl esters consist of the dibutyl esters.

4. A composition of matter of claim 2 in which the dialkyl esters consist of the di-2-ethylhexy1 esters.

dialkyl esters consist of the di-isooctyl esters.

6. A composition of matter of claim 2 in which the dialkyl esters consist of the di-2-octyl esters.

7. A composition of matter of claim 2 in which the dialkyl esters consist of the di-n-octyl esters.

8. A composition of matter comprising 100 parts by Weight of a vinyl resin selected from the group consisting of polymethylmethacrylate resins, vinyl chloride resins, and polyvinyl acetals and from 5 parts to 100 parts by weight of a plasticizer consisting essentially of dialkyl esters, in which the alkyl group has from 4 to 8, inclusive, carbon atoms, of a mixture of C aliphatic isomeric diacids consisting essentially of about 88% a-ethylsuberic acid, 12-25% a,a'-diethyladipic acid and 045% sebacic acid.

References Cited in the file of this patent UNITED STATES PATENTS 2,339,387 Endres Jan. 18, 1944 OTHER REFERENCES Bennett: Concise Chemical and Technical Dictionary, page 677, published 1947, Chemical Publishing Co., Inc., Brooklyn, N. Y. 

1. A COMPOSITION OF MATTER COMPRISING 100 PARTS BY WEIGHT OF A VINYL RESIN SELECTED FROM THE GROUP CONSISTING OF POLYVINYL ACETALS, AND FROM 5 PARTS TO 100 RESINS, AND POLYVINYL ACETALS, AND FROM 5 PARTS TO 100 PARTS BY WEIGHT OF A PLASTICIZER CONSISTING ESSENTIALLY OF DIALKYL ESTERS, IN WHICH THE ALKYL GROUP HAS FROM 4 TO 8, INCLUSIVE, CARBON ATOMS, OF A MIXTURE OF C10 ALIPHATIC ISOMERIC DIACIDS CONSISTING ESSENTIALLY OF ABOUT 60-88% A-ETHYLSUBERIC ACID, AND THE REMAINDER OF THE DIACIDS CONSISTING OF A MIXTURE OF A,A''-DIETHYLADIPIC ACID AND SEBACIC ACID. 